How does rust form? a. Through paint flaking off of a metal surface
b. Through a chemical reaction between iron and oxygen c. Through weathering
d. Through the physical mixing of iron and wa

Rusting is an oxidation reaction. The iron reacts with water and oxygen to form hydrated iron(III) oxide, which we see as rust. Iron and steel rust when they come into contact with water and oxygen – both are needed for rusting to occur.